Sofa



FIG. 1 is a front perspective view of an embodiment of my new sofa design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a left, side elevation view, with the right side elevational view being a mirror image thereof; and,

FIG. 4 is a rear elevation view thereof.

The broken line disclosure is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a sofa, as shown and described. 